Background and overview[1]
Methyl phenoxyacetate, English name is methylphenoxyacetate, CAS number is 2065-23-8, molecular formula C9H10O3. When the temperature is ≥30℃, it is colorless to slightly yellow liquid; when the temperature is <30℃, it is a white solid. Methyl phenoxyacetate can be used as a disinfectant or pharmaceutical intermediate or pesticide intermediate, with about 3,000 tons used worldwide every year. The product is stable, has a high flash point, is non-toxic and can be stored and transported.
Preparation[1]
Preparation method of methyl phenoxyacetate: using normal pressure liquid-solid phase esterification reaction, using aluminum phosphate molecular sieve as the catalyst, the preparation is completed by the following steps:
1) In a three-necked flask, add 1 g of methanol, 500 g of phenoxyacetic acid, 2.5-9.5 g of aluminum phosphate molecular sieve as catalyst, and 700 g of benzene, toluene or cyclohexane;
2) Heating reaction, reflux, dehydration, recovery of methanol and part of cyclohexane;
3) After the reaction is completed, filter out the aluminum phosphate;
4) Water-flush vacuum pump vacuum distillation to recover cyclohexane and remove heads;
5) The slide valve vacuum pump evaporates the finished product methyl phenoxyacetate, the content is >99.0%, and the weight is about 470 grams.
Apply[2]
CN201810226596.5 discloses a preparation method of 2,4-dichlorophenoxyacetate, which includes the following steps: S1) react phenol and methyl chloroacetate under alkaline conditions to obtain methyl phenoxyacetate ; S2) Methyl phenoxyacetate undergoes a selective chlorination reaction with a chlorinating agent under the action of catalyst A and catalyst B to obtain methyl 2,4-dichlorophenoxyacetate; the catalyst A is a Lewis acid; The catalyst B is a C5-22 thioether, thiazole, isothiazole, thiophene or their halogenated derivatives; S3) methyl 2,4-dichlorophenoxyacetate and alcohol perform transesterification reaction under the action of the catalyst , 2,4-dichlorophenoxyacetate is obtained; the alcohol is a C2-20 alcohol. The present invention uses methyl phenoxyacetate as raw material to carry out selective chlorination reaction, which improves the selectivity of the reaction, avoids the loss of active ingredients, greatly improves the yield of active ingredients, and reduces the amount of three wastes treated, the difficulty of treating three wastes and Processing costs.
References
[1] Preparation method of CN200810037748.3 methyl phenoxyacetate
[2]CN201810226596.5 Preparation method of 2,4-dichlorophenoxyacetate
